Chimney Stains? Here’s What They Mean

Most homeowners expect the sun to cause their chimneys’ vibrant color to fade over the years but what they do not expect is complete changes in color ranging from rust to black. These shocking color transformations can be worrisome. Knowing what these colors mean can inspire quicker action that might save dollars on chimney repairs in the long run. So, what’s causing your chimney to change colors?

Mold and Algae – The most common cause of your chimney staining is water damage. When water has been collecting inside the pores of chimney masonry, mold and algae can form. Algae will usually be green but mold can leave green black and even blue stains. When water makes its way into the brick and does not evaporate completely, it leaves lots of time for mold or algae to grow. Neglect over the years can cause a chimney to be totally overcome with mold or algae and lead to structural damage.

Soot and Creosote – The main cause of stains that appear black or brown is usually due to soot or creosote build-up. Drafting issues could send more smoke and incompletely combusted materials out of the chimney which would cause the staining or there could have been a chimney fire that ignited and went out without anyone knowing. These are serious issues and should be addressed immediately.

Water Damage – Chalky white stains are yet another indication that water is getting into your masonry. This may be the prelude to those green stains we mentioned earlier. The white stains are called efflorescence and happen as the water evaporates leaving salts behind, this is a natural process but if the damage is more serious it could lead to cracks that are later invaded by mold or algae.

Corrosion – If the metal parts of a chimney (such as the chimney cap, crown, or flashing) have been compromised – when it rains the water mingles with the corrosion to leave noticeable rust-colored stains on your chimney. This may not seem like such a big deal, but a corroded chimney cap, crown or flashing cannot do the job of keeping water out of your flue. That water will lead to a leaky chimney, this can weaken structural areas and send water pouring into your house. A chimney rebuild can be a costly enterprise. The best prevention is to quickly take care of a chimney crown, cap or flashing that is old and rusted.

Now that you understand what these colors may mean, the next step is a professional chimney inspection. A professional will be able to tell exactly which areas of your chimney are damaged and the extent of the work necessary. A DIY mindset can only get you so far in the realm of chimney repairs. We often find work that has been done incorrectly, insufficiently or “fixes” that have actually made the problem worse. Don’t rely on subpar repairs. We will inspect your chimney and get you the services you need to make sure your chimney is functioning at its absolute best. Call us and schedule your appointment today!